The present invention relates to chain stitch sewing machines and more particularly to an improved chain stitch sewing machine that includes a stitch skipping mechanism mechanically incorporated into the needle bar movement mechanism of a chain stitch sewing machine for allowing an operator to skip one or more stitches while the chain stitch sewing machine is operating.
Chain stitch sewing machines are often used to chain stitch sections of fabric together that will later be lock stitched together at a later step in the manufacturing process. Once the lock stitching has been accomplished, it is necessary to remove the chain stitching. It would be much easier to remove the temporary chain stitching if the line of chain stitches included several missed stitches which would allow a worker to easily grasp the chain stitched thread in a manner to easily pull on and unravel the section of chain stitching. It would be desirable, therefore, to have a chain stitch sewing machine that included a stitch skip mechanism that could be activated by an operator that would allow the operator to cause the chain stitch sewing machine to miss stitches while the stitch skip mechanism was activated.
It is thus an object of the invention to provide an improved chain stitch sewing machine having a needle bar movement mechanism including a pivoting needle bar drive lever having a needle bar attachment end, a pivot bushing disposed in a central portion thereof, and a hand wheel end mechanically linked to a drive motor through a crank shaft assembly of a chain stitch sewing machine such that, as a drive shaft of the drive motor rotates the crank shaft assembly, the needle bar attachment end of the pivoting needle bar drive lever is caused to reciprocate up and down in a timed fashion by pivoting against an exisiting hinge shaft having a bushing contact section concentrically aligned with other sections of the hinge shaft and positioned through the pivot bushing; the improvement comprising providing an operator activated hinge shaft angular orientation mechanism mechanically linked to an improved hinge shaft having two concentrically oriented end sections connected by an off-center bushing contact section that is dimensioned such that, when the improved hinge shaft is oriented at a first orientation by the operator activated hinge shaft angular orientation mechanism, the needle bar attachment end of the pivoting needle bar drive lever reciprocates between a normal upper and a normal lower position that causes the chain stitch swing machine to form a chain stitch during each cycle of operation; and that, when the improved hinge shaft is oriented at a second orientation by the operator activated hinge shaft angular orientation mechanism, the needle bar attachment end of the pivoting needle bar drive lever reciprocates between a raised upper and a raised lower position that causes the chain stitch swing machine to skip a chain stitch during each cycle of operation.
Accordingly, an improved chain stitch sewing machine with a stitch skip mechanism is provided.